Question about Cars & Trucks
I have a 1991 ford bronco i just changed the transmission filter and and fluid out and now it stalls in reverse, goes into forward gears fine and drives fine, only stalls in reverse? will go backwards if i rev motor above 1800 rpms, but stalls at idle?
is commonly caused by a dirty automatic idle speed control valve and
throttle valve but always run a OBD2 fault code as well as the
cleaning procedure. Buy a can of throttle valve cleaner (do not use
carburetor spray cleaner!) from NAPA or Carquest (made by CRC
chemicals) and spray it into the air intake while the engine is
running, use up about 1/2 the can, engine will try to stall hold the
speed up, shut it down and let it soak for 30 minutes, restart and
blow out the remaining fluid, shut it down and disconnect the
negative battery cable for 5 Min's to reset the base idle control. If
the above cleaning doesn't cure your issues you need to have the
computer controlled automatic idle speed control system diagnosed and
repaired by a dealer or electronic engine control repair shop.
This problem is commonly caused by a dirty automatic idle speed control valve and throttle valve but always run a OBD2 fault code as well as the cleaning procedure. Buy a can of throttle valve cleaner (do not use carburetor spray cleaner!) from NAPA or Carquest (made by CRC chemicals) and spray it into the air intake while the engine is running, use up about 1/2 the can, engine will try to stall hold the speed up, shut it down and let it soak for 30 minutes, restart and blow out the remaining fluid, shut it down and disconnect the negative battery cable for 5 Min's to reset the base idle control. If the above cleaning doesn't cure your issues you need to have the computer controlled automatic idle speed control system diagnosed and repaired by a dealer or electronic engine control repair shop.
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Posted on Jan 02, 2017
Before guessing at transmission problems, check the fluid level (car
warmed up, engine running in Park on level ground) and have the PCM
scanned for trouble codes FIRST.
Also note that many problems that show up as transmission issues are actually PCM or electrical, and may be external to the transmission.
Secondly, put a line pressure gauge ($55 shipped on Ebay, or visit a local trans shop) on the pressure test port and go for a drive to verify proper line pressure. Base pressure at idle in P,N,OD should be around 70psi and around 140psi in R. Max line pressure should be at least 190psi at WOT in 1st or 2nd, 225psi is optimum. If base pressure is low, trans or pump is worn out. If max pressure is low, check EPC solenoid. If reverse is slow to engage, and line pressure does not come up to at least 130psi in reverse, replace the boost valve with a Transgo 0.500" boost valve (easy fix in pan).
1-2 shift does not happen at WOT until you let off the gas: Best case: try replacing the TPS. Middle case: leak in the 2nd gear apply circuit (servo assembly or 1-2 accumulator). Double check by using the pressure gauge and watch for a big drop when the PCM commands 2nd gear. Worst case: poor line pressure rise.
1-2 Shift shudder at WOT; delayed or abnormal 1-2 shift; There's a problem ONLY on the 1-2 shift: 1-2 accumulator piston cracked or stuck cocked in the bore. Check the yellow spring inside the accumulator housing for breakage. Also, if the accumulator housing walls are scored, the housing must be replaced. Easy fix in the pan.
1-2 shift is delayed and harsh, may not shift into OD: Check TPS for smooth and linear electrical response over the entire range of motion. If not, replace.
Soft shifting, gradual performance degradation: Poor line pressure rise due to leaking boost valve, clogged EPC filter screen, failing EPC solenoid, or worst case: leaky seals throughout. Transgo HD2-C kit fixes first two without removing trans. Seal restorer may fix last problem, but probably R&R. Also try a transmission flush with BG brand products (Firestone stocks it).
Here are the common things that may be happening to your transmission to what you have described. As for your transmission fluid being burn, that is a sign that your transmission is slipping. Your going to have to service the transmission again fluid and filter changed. Since your doing that you may want to replace the boost valve and shift servo. I did mine on my 4L60E and have over 365,000 miles so far, replacing the boost valve every 60,000 mile and it's only $45.00 and take less the 5 min to replace and the servo is around the same price. I did do the upgrade and have the corvette boost valve and servo in my transmission which helps a lot. The other thing to is B&M has a electronic shift controlled modulator you can install your self which would give you 3 settings and works great with the upgrades mentioned above.
Good luck and hope this helps, keep me posted and try not to run the transmission too long with the burnt and dirty fluid. The dirt in the fluid will cause the electronic pressure control (EPC) valve to fail and will end up causing a $2,300.00 total transmission rebuilt over a simple $190.00 up grade and maintenance.
Posted on Jan 02, 2010
SOURCE: my dodge dakota it idles
It is actually hard to say without actually seeing the vehicle, but the target speed for your engine idle is around 750 RPM. The stalling after revving kind of depends on how high you are revving it and whether the engine is at operating temperature or not. This may be normal. Then again, it could be that the Idle Air Control (IAC) is not working properly.
The shifting from first to second at 4000 RPM sounds like a completely separate problem. This could be due to low transmission fluid level, sticking shift control solenoids, or possibly even a malfunctioning Vehicle Speed Sensor.
If the Check Engine light is on, have that checked first.
Posted on Feb 18, 2011
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